A light-emitting element such as a light emitting diode (hereinafter, called a “LED”) is used for various kinds of light-emitting devices. Owing not only to a decrease in size and an increase in efficiency of the LED compared with those of existing light sources utilizing discharge and radiation, but also an increase of a luminous flux of the LED that has been proceeded recently, it is possible to replace the existing light sources with the LED. For example, JP 2003-124528 A proposes a light-emitting module capable of realizing high optical output by mounting a number of LED chips on a card-shaped substrate at a high density.
The light-emitting module using a number of the LED chips described in JP 2003-124528 A is suitable for realizing a thin light-emitting module. However, since each LED chip is provided with an optical system that is constituted of an individual reflector or lens, an area of the whole module is increased.